From 34961c2a4fc18a7936fedb1c38e76dd9809980e3 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?J=C3=B8rgen=20Edelbo?= <jorgen.edelbo@mongodb.com>
Date: Fri, 2 Oct 2020 14:59:05 +0200
Subject: [PATCH] Correctly update case insensitive queries on indexed string
 columns

---
 CHANGELOG.md               |  2 +-
 src/realm/query_engine.cpp |  1 +
 test/test_query.cpp        | 14 ++++++++++++++
 3 files changed, 16 insertions(+), 1 deletion(-)

diff --git a/CHANGELOG.md b/CHANGELOG.md
index 40ff61a8d5c..92b0ba28751 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -5,7 +5,7 @@
 
 ### Fixed
 * <How to hit and notice issue? what was the impact?> ([#????](https://github.com/realm/realm-core/issues/????), since v?.?.?)
-* None.
+* If you make a case insignificant query on an indexed string column, it may fail in a way that results in a "No such key" exception. ([#6830](https://github.com/realm/realm-cocoa/issues/6830), since v6.0.0)
  
 ### Breaking changes
 * None.
diff --git a/src/realm/query_engine.cpp b/src/realm/query_engine.cpp
index 4193d9e5904..df36ac17580 100644
--- a/src/realm/query_engine.cpp
+++ b/src/realm/query_engine.cpp
@@ -367,6 +367,7 @@ std::string StringNode<Equal>::describe(util::serializer::SerialisationState& st
 void StringNode<EqualIns>::_search_index_init()
 {
     auto index = ParentNode::m_table->get_search_index(ParentNode::m_condition_column_key);
+    m_index_matches.clear();
     index->find_all(m_index_matches, StringData(StringNodeBase::m_value), true);
     m_results_start = 0;
     m_results_ndx = 0;
diff --git a/test/test_query.cpp b/test/test_query.cpp
index be95a63c8db..63ae82e4040 100644
--- a/test/test_query.cpp
+++ b/test/test_query.cpp
@@ -2556,7 +2556,9 @@ TEST(Query_StrIndexUpdating)
     auto col = t->add_column(type_String, "value");
     t->add_search_index(col);
     TableView tv = t->where().equal(col, "").find_all();
+    TableView tv_ins = t->where().equal(col, "", false).find_all();
     CHECK_EQUAL(tv.size(), 0);
+    CHECK_EQUAL(tv_ins.size(), 0);
     group->commit_and_continue_as_read();
 
     // Queries on indexes have different codepaths for 0, 1, and multiple results,
@@ -2570,7 +2572,9 @@ TEST(Query_StrIndexUpdating)
     t->create_object();
     group->commit_and_continue_as_read();
     tv.sync_if_needed();
+    tv_ins.sync_if_needed();
     CHECK_EQUAL(tv.size(), 1);
+    CHECK_EQUAL(tv_ins.size(), 1);
 
     // 1 -> multiple results
     group->promote_to_write();
@@ -2578,7 +2582,9 @@ TEST(Query_StrIndexUpdating)
     t->create_object();
     group->commit_and_continue_as_read();
     tv.sync_if_needed();
+    tv_ins.sync_if_needed();
     CHECK_EQUAL(tv.size(), 3);
+    CHECK_EQUAL(tv_ins.size(), 3);
 
     // multiple -> 1
     group->promote_to_write();
@@ -2586,14 +2592,18 @@ TEST(Query_StrIndexUpdating)
     t->remove_object(tv.get_key(1));
     group->commit_and_continue_as_read();
     tv.sync_if_needed();
+    tv_ins.sync_if_needed();
     CHECK_EQUAL(tv.size(), 1);
+    CHECK_EQUAL(tv_ins.size(), 1);
 
     // 1 -> 0
     group->promote_to_write();
     t->remove_object(tv.get_key(0));
     group->commit_and_continue_as_read();
     tv.sync_if_needed();
+    tv_ins.sync_if_needed();
     CHECK_EQUAL(tv.size(), 0);
+    CHECK_EQUAL(tv_ins.size(), 0);
 
     // 0 -> multiple
     group->promote_to_write();
@@ -2601,7 +2611,9 @@ TEST(Query_StrIndexUpdating)
     t->create_object();
     group->commit_and_continue_as_read();
     tv.sync_if_needed();
+    tv_ins.sync_if_needed();
     CHECK_EQUAL(tv.size(), 2);
+    CHECK_EQUAL(tv_ins.size(), 2);
 
     // multiple -> 0
     group->promote_to_write();
@@ -2609,7 +2621,9 @@ TEST(Query_StrIndexUpdating)
     t->remove_object(tv.get_key(1));
     group->commit_and_continue_as_read();
     tv.sync_if_needed();
+    tv_ins.sync_if_needed();
     CHECK_EQUAL(tv.size(), 0);
+    CHECK_EQUAL(tv_ins.size(), 0);
 }
 
 TEST(Query_GA_Crash)